152 



GENESIS OF THE ARIETID.E. 



Fir,. 25, 26. Views from the side and in section of Cal. Newberryi showing incomplete living chamber and 

 outlines of whorls. 



Fig. 27. View of suture made up from the last suture in Fig. 23 and the study of others. The abdomen 

 is projected, to show depth and narrowness of abdominal lobe. 



development of keel and channels, narrower abdomen in the whorls of the adult, 

 and in being, like the species of Central Europe, considerably smaller. The 

 largest specimen had just begun to pass into the first senile stage. The internal 

 or young whorls have pite similar to those of the young of Cal. raricostaium and 

 Cal. carusense. The sutures are similar to those of the normal species of Central 

 Europe, having broader lobes and saddles than is customary in the basin of the 

 Northeastern Alps. This agrees with other characteristics, which are essentially 

 similar to species from the European province. The second and smaller speci- 

 men, which is 80.5 mm. in diameter, has similar but straighter pilae. The 

 abdomen is broader and more depressed, and the channels better defined, but 

 how much of this is due to pressure cannot be stated. Both specimens have 

 been distorted b}f pressure. The first has been affected in such a way that it is 

 easy to restore the normal form, whereas in the second case it is not easy to 

 separate the results of pressure from the true characters. 



